5 Visual inspection – PISAPLOT

PISAPLOT plots the results of the PISAFIND analysis as a series of ellipses which reflect the size and shape of the objects as defined by their RESULTS parameters. The ellipses can be annotated with their index number to provide a cross-reference to the object list. The plot may be overlaid on an existing image for a direct comparison of the results.

The program uses AGI [7] the graphics database so that suitable tasks, such as the KAPPA [6] routine CURSOR, can be used to get positional information. PISAPLOT has many parameters which control such things as the line thickness, line colour, the upper and lower bounds of the plot axis, so that the output can be modified for presentation and comparison purposes.

Perhaps the most likely use of PISAPLOT is to overlay a results file over a previously displayed image. This is achieved using the OVERLAY parameter

  # pisaplot overlay

If the plotting device has an overlay plane then the present contents of it may be cleared using the CLEAR parameter

  # pisaplot overlay clear

The colours of the plotted ellipses are controlled using the PALNUM parameter. If the graphics device allows colour then different pen numbers may be used for successive plots using the OVERLAY option. So for instance a group of objects separated from the main results by some criterion (being stellar) may be plotted in one colour and the others in another colour. The pen colours are set by PGPLOT and are:

Pen Number Colour

0 background colour
1 foreground colour
2 red
3 green
4 blue
5 cyan
6 magenta
7 yellow
8 orange

and so on up to pen 16.

After PISAPLOT has been run these colours can be superseded by using the KAPPA palette facilities PALDEF and PALENTRY, but note that any subsequent runs of PISAPLOT will reinstate the PGPLOT default colours so using the KAPPA facilities should be delayed until all different sets of objects have been displayed. The KAPPA palette pen numbers correspond to PALNUM values (hence the parameter name).